and when either '.git' or '.svn' is present in the current directory (with the intention of only forcing extra tests on the author side) - or when the PERL_STRICTURES_EXTRA environment variable is set, in which case

use strictures 1;

is equivalent to

use strict;
use warnings FATAL => 'all';
no indirect 'fatal';
no multidimensional;
no bareword::filehandles;

Note that _EXTRA may at some point add even more tests, with only a minor version increase, but any changes to the effect of 'use strictures' in normal mode will involve a major version bump.

If any of the extra testing modules are not present, strictures will complain loudly, once, via warn(), and then shut up. But you really should consider installing them, they're all great anti-footgun tools.

I've been writing the equivalent of this module at the top of my code for about a year now. I figured it was time to make it shorter.

Things like the importer in 'use Moose' don't help me because they turn warnings on but don't make them fatal - which from my point of view is useless because I want an exception to tell me my code isn't warnings clean.

Any time I see a warning from my code, that indicates a mistake.

Any time my code encounters a mistake, I want a crash - not spew to STDERR and then unknown (and probably undesired) subsequent behaviour.

I also want to ensure that obvious coding mistakes, like indirect object syntax (and not so obvious mistakes that cause things to accidentally compile as such) get caught, but not at the cost of an XS dependency and not at the cost of blowing things up on another machine.

Therefore, strictures turns on additional checking, but only when it thinks it's running in a test file in a VCS checkout - though if this causes undesired behaviour this can be overridden by setting the PERL_STRICTURES_EXTRA environment variable.

If additional useful author side checks come to mind, I'll add them to the _EXTRA code path only - this will result in a minor version increase (i.e. 1.000000 to 1.001000 (1.1.0) or similar). Any fixes only to the mechanism of this code will result in a subversion increas (i.e. 1.000000 to 1.000001 (1.0.1)).

If the behaviour of 'use strictures' in normal mode changes in any way, that will constitute a major version increase - and the code already checks when its version is tested to ensure that

use strictures 1;

will continue to only introduce the current set of strictures even if 2.0 is installed.